Small Craft Advisory 152, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
430 AM AST THU FEB 21 2008

.ANALYSIS AND UPPER LEVELS...THE WX PICTURE THIS MORNING LOOKS VERY
SIMILAR TO THE PAST COUPLE OF DAYS. THE EXCEPTION BEING THAT THE LOW
JUST EAST OF KODIAK IS MUCH WEAKER THAN ITS PREDECESSORS. A FRONT
STRETCHING NE FROM THE LOW IS EVIDENT ON RADAR IMAGERY JUST SOUTH OF
MIDDLETON ISLAND AS OF 12Z. THIS FRONT WILL MAKE SLOW BUT STEADY
PROGRESS NORTH CRASHING ONTO THE NORTH GULF COAST THIS AFTERNOON. THE
PRESSURE GRADIENT IS TIGHTENING UP QUICKLY THIS MORNING RESULTING IN
ANOTHER DAY OF STORM FORCE WINDS JUST OUTSIDE PRINCE WILLIAM SOUND
AND GUSTY E-W GAPS WINDS...ESPECIALLY ALONG TURNAGAIN ARM.

.MODEL DISCUSSION...ALL MODELS HAVE A GOOD HANDLE ON THE STRENGTH AND
POSITION OF THE LOW CURRENTLY. CONSENSUS SAYS THAT THE LOW WILL STALL
NEAR THE BARREN ISLANDS WHILE WEAKENING THROUGH FRIDAY. NOT TOO MUCH
FOR THE MODELS TO DISAGREE ON OUT WEST AS A RIDGE BUILDS OVER THE
WESTERN BERING...TIGHTENING THE PRESSURE GRADIENT IN THE EASTERN
BERING. MODELS DIVERGE A BIT IN THE FAR WESTERN BERING BEGINNING
FRIDAY IN REGARDS TO AN APPROACHING NORTH PACIFIC LOW. OVERALL THE
LOW IS EXPECTED TO SKIRT JUST WEST OF ATTU ISLAND WITH A WARM FRONT
TO DRAG ACROSS THE WESTERN ALEUTIANS.

.SHORT TERM FORECAST...ANOTHER DAY OF STRONG WINDS AND RAIN ALONG THE
NORTHERN GULF COAST. THERE WILL BE MORE OF A MIX OF RAIN AND SNOW BY
LATER IN THE DAY AS COLD AIR BEING WRAPPED AROUND THE LOW MOVES
NORTHWARD. AS THE FRONT MOVES ONSHORE LATER TODAY AND COLDER AIR
SLOWLY WORKS IN...STEADIER, HEAVIER SNOWS WILL FALL IN FAVORED
UPSLOPE AREAS AROUND PRINCE WILLIAM SOUND. PRECIP BECOMES MORE
SHOWERY ON FRIDAY AS THE LOW WEAKENS AND UPPER SUPPORT IS LOST THANKS
TO AN ADVANCING RIDGE FROM THE WEST.

GUSTY NORTH WINDS ARE BEING PRODUCED BY A TIGHT PRESSURE GRADIENT
BETWEEN THE LOW NEAR KODIAK AND THE RIDGE TO THE WEST. THE WINDS...IN
COMBINATION WITH SNOW SHOWERS IS DRASTICALLY REDUCING VISIBILITIES
ACROSS ALL OF THE EASTERN BERING. LOCALLY STRONGER GUSTS HAVE BEEN
NOTED SOUTH OF THE PRIBILOFS DUE TO AN ACCELERATION OF THE WINDS OFF
THE ICE PACK. THE SCENARIO WILL LAST THROUGH FRIDAY UNTIL THE RIDGE
MOVES OVERHEAD AND WINDS DIMINISH. THE WESTERN ALEUTIANS BEGIN TO GET
SLAMMED BY GALE TO STORM FORCE SOUTH WINDS IN ADVANCE OF AN
APPROACHING NORTH PACIFIC LOW BEGINNING FRIDAY AFTERNOON. THE
EASTWARD ADVANCEMENT OF THIS SYSTEM WILL BE MINIMIZED BY THE STRONG
RIDGE POSITIONED IN THE EASTERN BERING.

.LONG TERM FORECAST...MODELS INDICATE BERING SEA UPPER RIDGE WILL BE
CUT OFF AT ITS BASE OVER THE WEEKEND AND RETREAT UP TO THE CHUKCHI
SEA WHERE IT WILL REMAIN THROUGH NEXT WEEK. THIS WILL KEEP MOST OF
THE MAINLAND DRY WITH SEASONABLE TEMPERATURES. THE PERSISTENT
NORTHERLY FLOW ALOFT OVER MAINLAND ALASKA WILL SET UP THE POTENTIAL
FOR STRONG NORTHERLY WINDS THROUGH CHANNELED AREAS OF SOUTHCENTRAL.
STORMINESS WILL BE HELD TO THE SOUTHERN PORTION OF THE FORECAST AREA
FROM THE ALEUTIANS TO KODIAK ISLAND.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...STORM 120.
         HEAVY FREEZING SPRAY 165 179 185 412 414.
         GALE 125 130 138 140 170 171 175 176 351 352 411.
FIRE WEATHER...NONE.

JCA